REFLECTOMETRIC MEASUREMENT OF DENSITY AND MAGNETIC FLUCTUATIONS IN ICRF-DRIVEN WAVES

Reflectometric techniques have been applied to the GAMMA 10 tandem mir ror to measure density and magnetic fluctuations associated with elect romagnetic plasma waves in the ion cyclotron range of frequency (ICRF) . The excitation and propagation of ICRF-driven waves are studied by r eflectometers in order to achieve efficient heating of plasmas. The ra dial profile of the fluctuation level is expected to give the depositi on profile of the heating power. A cross-polarization scattering diagn ostic system is also installed in the central cell of GAMMA 10. An inc ident ordinary (extraordinary) wave is converted to an extraordinary ( ordinary) wave by magnetic fluctuations. The converted wave can propag ate through a cut-off layer and reach the detector. The level of magne tic fluctuation (about 10(-4)) is evaluated for the ICRF-driven waves. (C) 1997 Elsevier Science S.A.